1. Field of the Invention
The present invention relates to a linear vibrator, and more particularly, to a linear vibrator having improved performance and lifespan by preventing a vibration amplitude from being restricted when a vibration part is in vibration.
2. Description of the Related Art
Recently, the release of personal mobile terminals having large LCD screens onto the market has been rapidly increased so as to facilitate user convenience. Therefore, personal mobile terminals have adopted a touch screen scheme and use a vibration motor in order to generate vibrations when the screen is touched.
The vibration motor is a part using a principle of generating an electromagnetic force to convert electrical energy into mechanical vibrations. The vibration motor is mounted on a personal mobile terminal and has been used to indicate an incoming call in a silent mode.
The related art has used a scheme of generating a rotational force to rotate a rotating part of unbalanced mass, thereby obtaining mechanical vibrations. That is, the related art has used a scheme of obtaining mechanical vibrations by performing a rectifying action on the turning force through contact between a brush and a commutator.
However, the brush type structure using the commutator causes mechanical friction and electrical sparking, and generates foreign objects while the brush passes through the space between segments of the commutator when the motor rotates, thereby shortening the lifespan of the motor.
In addition, when voltage is applied to the motor, it takes time to reach the target amount of vibrations, due to rotation inertia, which makes it difficult to implement appropriate vibrations on the touch screen.
In order to overcome the problems of lifespan and response characteristics of the motor and implement the vibration function of the touch screen, a linear vibrator has been mainly used.
The linear vibrator does not use the rotational principle of the motor to generate vibrations. To generate vibrations, the linear vibrator generates resonance by periodically generating an electromagnetic force obtained through a spring mounted in the vibration motor and a mass body hung on the spring according to a resonance frequency.
However, a linear vibrator designed to be vibrated in a vertical direction can generate vibrations by vertically moving the mass body mounted therein, such that the entire thickness of the linear vibrator is able to be limited.
However, personal mobile terminals adopting the linear vibrator have a limited mounting space available for the linear vibrator, such that there is a problem that the thickness of the linear vibrator cannot be sufficiently increased so as to secure a certain level of vibratory force in the linear vibrator.
Therefore, research into securing sufficient vibratory force is urgently needed in order to improve the performance and lifespan of the linear vibrator.